To study structure-activity relationships in the apomorphine molecule, with respect to emetic effects and other pharmacological properties. To gain further insight on the role of apomorphine and of certain other systems which are congeners and fragments of the apomorphine molecule, as agonists capable of exerting dopaminergic effects, especially insofar as these effects bear upon emetic activity and upon possible value of these compounds as anti-Parkinsonism agents and as dilators of the renal vascular bed. In addition, these compounds will be explored for other pharmacological actions, and the metabolism of these agents will be investigated.